Stoker system



A. M. HUNT STOKER SYSTEM July '29, 1930.

2 Sheets-Sheet 1 Filed Aug. 50, 1926 July 29, 1930. A. M. HUNT STOKER SYSTEM "Filed Aug. 30, 1926 2 Sheets-Sheet 2 JWKWQ ESQ M0 Patented July 29, 1930 Hairs srA'rss .PATEVNTV- OFFICE ANDREW M. HUNT, or BERKELEY, CALIFQRNIA,ASSIG1\TOR TO THE STANDARD sroxnn COMPANY, rnconrona'rnn, A CORPORATION or DELAWARE sroimn. SYSTEM v Application filed August 30, 1926. Serial No. 132,357.

method. and apparatus for so conditioning and supplyng the fuel to the fire'that the stack loss will be reduced, without interference with the functioning of the coal supplying means. Y

I propose to mix with the fuel at some point in its travela predetermined and controlled amount of a consolidating or coalescing agent which will be sufiicient to cause the smaller particles to lump together and/0r adhere to larger pieces so as to be held against escape upward with the draft gases when the. fuel is fed on to the fire, and which consolidating agent will be delivered at such place. as not to be interfered with by the conveyed fuel and I will not be present in such quantity or manner as to interfere with the operation of the mechanical means for supplying the fuel to' the fire. I

In the accompanying drawings illustrating a specific embodiment of one. form of appara tus for carrying out themethod of this invention I v Fig. 1 is adiagrammatic plan View of a locomotive stoking system, and I Fig. 2 is, a diagrammatic vertical sectional view of same. 1

The usual fuel supply, for instance ofscoal to a locomotive stoker, contains among the larger lumps of fuel a. considerablejpercentage of smaller particles approaching dust in fineness, and when the distributing means of the stoker throws or blows the coal over the fire the rising gases tend to lift these finer particlesupward and carrythem away. I

have discovered that this loss of fuel may be greatly reduced by miXingin with the lumps and particles before they reach the fire an agglomerating medium adhering to the par-.

ticles and acting by mixture to stick the particles together in larger pieces or causing the particles to adhere to larger lumps of the fuel, so that the fuel as it isdistributed over the fire bed consists practically entirely of relatively-large particles and lumps, which are carried down on to the fire and burned as fuel, and do not escape unburned.

- The effective lifting force of the draf above the 'fire bed is substantially inversely proportional to the linear size of thefuel particle being fed to the fire, the weight ofeach fuel particle increasing as the cube of its linearsize while the area exposedto the lifting force increases as the square thereof. Consequently, by increasing thesize of the particles as they are fed onto the fire, the tendency of the draft reduced. A r The material to be mixed With'the fuel gases to lift them is proportionately particles is such as'to have a surface, affinity."

for the fuel so as towet the same and spread a surface film over each individual particle with the film covering of each particle adheringto its particle tenaciously and presenting a peripheralsurface having a strong tendency to stick to other similarly surfaced particles and cohering thereto to bind a number of particles together. I have discovered that by properly supplying and, inter-mixing such a medium with the fuel as it is on its way to the fire, the fuel particles may be made to cling together into larger lumps very" strongly, the cohering surface films due to surface tension fastening themselves together and thus binding the particles or agglutinating a large number of particles into lumps or on tothe surface of larger pieces. Too large an excess of the medium will tend to break up this coherence between the film coverings, and this separating action will particularly take place wherever the excess is sufficient to submerge or drown the fuel. Ihave'fo und, however, that by introducing a binding medium, such as, water, in proper amount during the feeding'of-the fuel, such as coal, andv mixing intimately with thevparticles,the film V forming an agglutinating action is very pronounced. The amount of water necessary. to form the agglutmatmg film W111, of course,

vary in practice. The amount should not be large enough to cause the fuel to assume a liquid or quick condition, such as would cause the lifting mechanism to fail in its function. In practice I have found that a relatively small amount is sufficient, being for average conditions or the locomotive coal in the neighborhood of 5% by weight of the fuel, so that the subsequent vaporizing of the moisture in the firebox is accompanied by only a negligibly small absorption of heat and is only a small part of the gain of heat due to the burning of the agglutinated particles. Other binding mediums may be used such for instance as a combustible oil or a mixture of combustible granular material, such as sawdust with water, or with oil, in sufficient quantity to providethe agglutinating film to the fuel particles. For locomotive strokers as illustrated in the. figures of the drawings,

water is preferable for .reasons of economy and availability since the use of other special materials would not only be more expensive but would require special storage means and special filling'stations to be maintained.

In the locomotive system illustrated in the drawing the tender Tof the locomotive gen erally designated at L supplies coal to the locomotive fire box F over grate G by means of theifuel conveyor conduit C containing the rotatable conveyor screw means S driven from the engine N on the tenderas indicated. The' steam supply for the engine N is received from the locomotive boiler from the piping and valve device 59, which valve device may be controlled by the fireman through the handle and bell crank lever 61, the control being such that by movement of the handle the fireman can cause the conveyor screw means S to rotate to feed the coal forward orcan eifect reverse rotation so as to back the conveyor feedor can stop the IOtltlOIlOf the screwaltogethcr. The coal in the tender passes down through the opening shown into the trough 22 where the portion 23 of the conveyor breaks the larger lumps of coal against the projections B. The coal comprising lumps of various sizes and including the finer particles is fed by the conveyor screw means S through the conveyor tube 0 to the elbow E passing upward to an opening above the level of the fire on the grate G, the coal being distributed over the fire bed by jets of steam from the distributor head D. While the coal is thus being fed to the fire, and preferably at a point such as P, the wetting and agglutinating medium, such as water, is added andis thoroughly mixed with the coal as the same is pushed forwardly by the remaining portion of thescrew. In practice, in the type of stroker illustrated, the coal does not completely fill the conveyor mechanism until shortly before it passes into the bend of elbow E, an average condition being somewhat as indicated in the dotted line in Fig. 2. The

flow of the agglutinating medium is therefore uninterrupted and not interfered with and has opportunity to permeate the fuel somewhat before being further intermixed by the screw before passing into the bend of the elbow E.

In the specific system shown in the drawings the. water is supplied from the tank 20 of the tender through pipe 21 having the valve22 mechanically controlled through the lever arm connection 24 by the control crank 61 of the engine N so that When the engine is driven to drive the screw S to feed the coal forward, the valve 22 will be open, but under all other conditions of the engine the valve will be mechanically closed. The water pipe 21 is also provided with the hand control valve 25 positioned adjacent the handle 60 of the engine N so that the fireman can turn off the water supply independently of the interlocking mechanical control of the valve 22. The pipe 21 is continued by the flexible section 26 to the pipe 27 on the locomotive leadingto the nozzle 28;opening into the conveyor C at the point P. This nozzle 28 is of such a size as to mechanically give the proper supply of water under the average head in the tender tank 20, a trap pocket K being provided in the tank to trap and hold a suflicient supply of water for the pipe 21 when the level of the supply in the tank tends to fall below that required for the feed to the conveyor. The conduitC may also be provided with a lower overflow opening such as 80 to permit any excess water to drain off from the fuel 4 In this; stoker system the proper supply of the water to the coal is mechanically regulated by the correct sizing of the nozzle 28' and mechanically contrbnedby the connection of the valve 22 to the handle 60' of the engine N. All that the fireman has to do is to be sure'that the valye 25 is open under normal running conditions of the engine. The coal never becomes so wetted as to interfere with the proper firing of the locomotive and the heat from the fire under all normal conditions is sufficient to prevent the freezing of the coal and watermixture forward of the point P. Even if this mass does become frozen in cold weather when the locomotive is not in use, it is easily broken because it is simply made up of thin frozen films of moisture connecting the particles of coal together. The moist core of coal as it reaches the elbow E is in plastic easily fefd condition and passes smoothly upward through the elbow to the mouth where it overflows and is distributed outward over the fire bed by the jets of steam from the distributor head D. I These jets of steam may be directed somewhat downward so as to have a component counter to the upward tendency of the rising gases of the fire. The action of the distributing jets is to spread the fuel outward in all directions and carry it to all parts of the fire bed, the wet agglutinated condition of the particles of the coal mass holding them together in lumps and gobs so that they pass heavily downward on to the fire and are not lightly floated upward on the rising gases. The result is that practically all of the fuel is fed on to the fire bed without substantial stack loss, and without clogging or reducing the eificiency of the stoking means.

It is obvious that other means differently arranged may be used to apply the agglomera-ting mediumlto the coal, the preferred means varying, of course, with the particular type of stoking apparatus used and with the type and consistency of the fuel being used. The invention is not confined to the specific apparatus shown or described, but is intended to cover such modifications thereof that fall within the scope of the following claims.

I claim:

1. In a locomotive, a conveyor having a rotary screw for feeding fuel into the combustion chamber from a point of storage, an engine for operating said conveyor, a valve for controlling said engine, means for supplying an agglut-inating medium to the fuel in said conveyor at a point along said screw so as to thoroughly mix the fuel and agglutinating medium and to agglomerate the fine particles into larger aggregates, a valve for controlling said supply of agglutinating medium, and means for simultaneously controlling said valve controlling said engine and said valve controlling the supply of said agglutinating medium, said last recited means comprising separate cranks one for each valve and a connection between said cranks.

2. In a locomotive, a conveyor for feeding fuel into the combustion chamber from a dium independently of the level of the water in said water compartment.

4-. The combination with a locomotive and a tender having a water compartment for supplying the locomotive system, of a mechanically operated conveyor for feeding fuel into the combustion chamber of the locomotive from the tender, means for supplying an agglutinating medium to the fuel in said conveyor so as to agglomerate the fine particles into larger aggregates, means for controlling the supply of said medium according to the mechanical control of the operation of said conveyor, and a trap pocket within said water compartment adapted to maintain said supply of said medium independently of the'level of the water in said water compartment.

ANDREW M. HUNT.

point of storage, an engine for operating said conveyor, a valve for controlling said engine,

' means for supplying an agglutinating medium to the fuel in said conveyor so as to agglomerate the fine particles into larger aggregates, a valve for controlling said supply of agglutinating medium, a handle, and separate mechanical connections from the two valves to said handle, said handle operating through said separate mechanical connections to simultaneously control said valve controlling said engine and said valve controlling the supply of said agglutinating medium.

3. The combination with a locomotive and a tender having a water compartment for supplying the locomotive system, of a mechanically operated conveyor for feeding fuel into the combustion chamber of the locomotive from the tender, means for supplying an agglutinatlng medium to the fuel in said conveyor so as to agglomerate the fine particles into larger aggregates, means for controlling the supply of said medium according to the mechanical control of the operation of said conveyor, and independent means withm said tender for maintainlng said supply of me- 

